Current hearing aid fitting systems and processes are generally complex, relying on specialized instruments for operation by hearing professionals in clinical settings. For example, a typical fitting process may include an audiometer for conducting a hearing evaluation, a program for computing prescriptive formulae, a hearing aid programming instrument to program computed fitting parameters, a real ear measurement instrument, a hearing aid analyzer, calibrated acoustic transducers, sound proof room, etc. These systems, with methods and processes associated thereto, are generally not suitable for administration by a hearing impaired consumer in home settings.
Characterization and verification of a hearing aid generally requires presenting sound stimuli to the microphone of the hearing device, referred to herein generically as a microphonic or acoustic input. The hearing aid may be worn in the ear during the fitting process, for what is referred to as “real ear measurements” (REM), or it may be placed in a test chamber for characterization by a hearing aid analyzer. Tonal sound is typically used as the primary test stimuli, but other sounds such as a synthesized speech spectrum noise, or “digital speech,” may be applied to the hearing aid microphone. Real life sounds are generally not considered for determination of fitting parameters which are typically computed by a prescriptive formula. Hearing aid users are generally asked to return to the dispensing office following real-life listening experiences to make the necessary fitting adjustments for the fitting parameters. When real life sounds are used for evaluation or fitting, calibration of test sounds at the microphone of the hearing aid is generally required, involving probe tube measurements by REM instruments, or a sound level meter (SLM). Regardless of the particular method used, conventional fittings generally require clinical settings to employ specialized instruments for administration by trained professionals. The term “hearing device”, is used herein to refer to all types of hearing enhancement devices, including hearing aids prescribed for the hearing impaired, and personal sound amplification products (PSAP) generally not requiring a prescription or a medical waiver.
Programmable hearing aids rely on adjustments of programmable electroacoustic settings, referred to herein generally as fitting parameters. Similar to hearing assessments and hearing aid prescriptions, the programming of a hearing aid generally requires specialized instruments and involvement of a hearing professional in a clinical setting to deal with a range of complexities related to hearing aid parameter adjustment and programming, particularly for an advanced hearing aid which may incorporate a large number of adjustable and inter-related fitting parameters.
Resorting to consumer computing devices, such as Windows-based personal computers, smartphones, and tablet computers, to produce test stimuli (sounds) for hearing evaluation is generally problematic for many reasons, including the variability in sound characteristics of output produced by consumer quality audio components. Furthermore, the internal speakers or headphone speakers used are not easily calibrated and/or simply do not meet audio specifications and standards of audiometric and hearing aid evaluations. For example total harmonic distortion (THD), accuracy of amplitudes, noise levels, frequency response, etc.
Conventional fitting processes are generally too technical and cumbersome for administration by a non-expert person. For the aforementioned reasons among others, the fitting process for a programmable hearing device is generally not available to consumers for self-administration at home. A hearing aid dispensing professional is typically required for conducting one or more steps of the fitting process, from calibrated hearing evaluation and hearing aid recommendation and selection to prescription computation and programming of the hearing device. This process often requires multiple visits to incorporate the user's subjective assessment from real life listening experiences after the initial fitting. As a result of the above, the cost of professionally dispensed hearing aids can easily reach thousands of dollars, and almost double that for a pair of advanced hearing aids. The unaffordability of programmable hearing aids represents a major barrier to potential consumers for an electronic hearing device often costing under $100 to manufacture.